/*
 * Copyright (c) 2010, Joshua Lackey
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 *     *  Redistributions of source code must retain the above copyright
 *        notice, this list of conditions and the following disclaimer.
 *
 *     *  Redistributions in binary form must reproduce the above copyright
 *        notice, this list of conditions and the following disclaimer in the
 *        documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * circular_buffer
 *
 * This class is based heavily on the GNU Radio circular buffer.  While this
 * class was written from scratch and contains ideas not present in the GNU
 * Radio implementation, the GNU Radio circular buffers were used as a
 * reference while developing this class.
 *
 * This is more a warning that the above BSD-style license may not be the only
 * copyright that applies.
 */

#pragma once

/*
 * XXX If read doesn't catch up with write before 2**64 bytes are written, this
 * will break.
 */

#include <pthread.h>
#ifdef _WIN32
#include <Windows.h>
#endif

class circular_buffer
{
public:
  circular_buffer (const unsigned int buf_len, const unsigned int item_size =
		   1, const unsigned int overwrite = 0);
   ~circular_buffer ();

  unsigned int read (void *buf, const unsigned int buf_len);
  void *peek (unsigned int *buf_len);
  unsigned int purge (const unsigned int buf_len);
  void *poke (unsigned int *buf_len);
  void wrote (unsigned int len);
  unsigned int write (const void *buf, const unsigned int buf_len);
  unsigned int data_available ();
  unsigned int space_available ();
  void flush ();
  void flush_nolock ();
  void lock ();
  void unlock ();
  unsigned int buf_len ();

private:
#ifdef _WIN32
    HANDLE d_handle;
  LPVOID d_first_copy;
  LPVOID d_second_copy;
#endif
  void *m_buf;
  unsigned int m_buf_len, m_buf_size, m_r, m_w, m_item_size;
  unsigned long long m_read, m_written;

  unsigned int m_overwrite;

  void *m_base;
  unsigned int m_pagesize;

  pthread_mutex_t m_mutex;
};
